1. Field of the Invention
Embodiments described herein relate generally to a method of manufacturing a transparent resin composition containing polycarbonate resin and acrylic resin.
2. Description of the Related Art
Polycarbonate resin is excellent in transparency, dimensional stability and resistance to impact, and has thus been conventionally used in various applications, such as automobiles, electronic devices and houses. However, although the resin has excellent characteristics as described above, it is inferior in surface hardness and resistance to ultraviolet light. In consideration of these deficiencies, research and development with respect to mixing the resin with acrylic resin has been promoted.
Patent literature 1 discloses a technique for obtaining transparent resin materials by kneading raw materials of polycarbonate resin and methacrylic resin with a high-shear processing device comprising an internal feedback-type screw.
In this prior art, raw materials of polycarbonate resin and methacrylic resin are melted and kneaded near their melting point at 200 to 240° C. By this kneading, the dispersal phase of methacrylic resin having a diameter of 300 nm or less, preferably 100 nm or less, is nano-dispersed into the polycarbonate matrix phase uniformly and densely. Thus, the kneaded resin materials become transparent.
The patent literature further discloses the following technical matters. When raw materials are mixed using a twin-screw melting/kneading device, the dispersal phase is larger than the wavelength of the visible range. Thus, the kneaded resin materials are not transparent, and become whitish.